(Invited) Conformal Deposition for 3D Thin-Film Batteries

Abstract

For the application of durable micro-storage for autonomous systems and implants, 3D thin-film batteries are leading candidates. Lithium ion batteries have the highest energy density of all known systems and are thus the best choice also for these rechargeable micro-batteries. Since liquid electrolyte based batteries present safety issues and limitations in size and design, pure solid state devices are considered particularly for miniaturization. Planar thinfilm lithium and lithium ion batteries are at present commercially available but have limited capacity (<1mAh/cm2). The capacity can be increased by coating the thin-film stacks on micro-or nanostructured surfaces (3D thin-film batteries). The main advantage of thin-film (TF) batteries is that its power can be increased by scaling down the film thickness. The main technological challenges in the introduction 3D TF batteries are pinhole-free and chemically uniform conformal coating of the cathode, electrolyte and anode thin-film stack.